1. Field of the Invention
The present invention relates to an ink-jet recording head and an ink-jet cartridge which are used for an ink-jet recording apparatus and, more particularly, to a bubble jet recording head and a bubble jet cartridge.
2. Brief Description of the Related Art
An ink-jet recording system, wherein minute droplets generated out of an ink are adhered to recording media such as a sheet of paper, is a sort of recording systems having characteristic properties such that noise generation during recording is extremely low, a high-speed recording is capable and a recording even onto a sheet of plain paper is allowable. Among the ink-jet recording systems, so called a "bubble jet" recording mode, which employs an exothermic device as an energy generating means for ejecting the ink droplets, has recently been attracting a particular attention.
As a method for manufacturing the ink-jet recording head in the bubble jet recording mode, a technology constituted below has been known, comprising steps of:
arraying a plurality of ejecting energy generating means formed of such as exothermic devices for generating each of thermal energies used for ejecting an ink onto a substrate; PA1 fixing the substrate onto a base plate; PA1 providing a top board with trenches, each of which constitutes an ink path correspondent to each of the exothermic devices; PA1 providing the trenched top board also with each of ejecting ports formed correspondingly to each of the ink paths; PA1 providing the trenched top board still also with a concavity forming a common liquid reservoir connected to each of the ink paths; PA1 contacting the trenched top board with the substrate to fix the board on the substrate by an aid of a pressurizing member connected onto the base plate; PA1 assembling an ink supplying member for supplying the inks onto the trenched top board; and PA1 further filling an encapsulant such as a polymerized silicone plastic resin or the like between the trenched top board and the substrate for a purpose of preventing leakage of any liquids. PA1 an ejecting port which ejects an ink; PA1 a substrate provided with an ejecting energy generating means which is used for ejecting ink droplets; PA1 a trenched top board provided with trenches, which constitute partly a plurality of ink paths respectively connected to the ink ejecting ports, and provided with a concavity, which constitutes partly common liquid reservoirs respectively connected to the plurality of the ink paths; and PA1 an elastic member which pressurizes to fix the trenched top board onto the substrate; wherein: PA1 the substrate and the top board are contacted so that the ejecting energy generating means and the trenches partly forming the ink paths coincide with each other to form the ink paths; PA1 a contacting part of the trenched top board to be contacted with the substrate is composed of a contacting surface of the ink paths to be contacted with the substrate and of another contacting surface of the common liquid reservoirs to be contacted with the substrate; and PA1 the contacting surface of the common liquid reservoirs to be contacted with the substrate is inclined toward a substrate surface with respect to the contacting surface of the ink paths to be contacted with the substrate.
As one of the ink-jet heads constituted as mentioned above, a pressurizing member having a constitution to generate a piping line pressure, thereby to press approximately uniformly an area located on the top board, which corresponds to an ink path forming area provided adjacently to the ink ejecting ports of the trenched top board, has been disclosed in the Japanese Laid-open Patent Application Number: 3-101955 (1991). In the ink-jet heads constituted as aforesaid, it is desirable that a contacting part of the ink path area formed on the trenched top board to be contacted with the substrate adheres assuredly to the substrate.
Namely, if the contacting part of the ink path area formed on the trenched top board to be contacted with the substrate does not adhere assuredly to the substrate, the ejecting pressure generated by the exothermic devices during a recording operation is dispersed and spreaded to the adjacent ink paths. This phenomenon is liable to make an ink ejecting speed unstable, resulting in staggered flying trajectories of the ink droplets, and also liable to disturb normal meniscus positions in the adjacent ink paths except for that which should eject the ink, resulting in a turbulent printing. All of above-mentioned results degrade a recording quality.
Accordingly, another constitution, wherein a stepwise level difference is formed newly on the trenched top board so that the contacting area of the common liquid reservoirs to be contacted with the substrate turns lower compared with another contacting area of the ink path to be contacted with the substrate in order that the contacting area of the ink paths should contact assuredly with the substrate, has been further disclosed in the Japanese Laid-open Patent Application Number: 3-101957 (1991).
In the ink-jet head disclosed in the Japanese Laid-open Patent Application Number: 3-101957 (1991), however, only a bump-shaped projection, which is provided on a rear surface of the common liquid reservoirs, actually contacts with the substrate as the contacting area of the common liquid reservoirs to be contacted with the substrate. Consequently, the encapsulant, which should fill vacancies located between the substrate and the trenched top board, intrudes frequently through the vacancies, where the trenched top board does not contact with the substrate, into the liquid reservoirs. When the intruded encapsulant reaches the ink paths, it induces clogging failures of the paths. Accordingly, a still another constitution for preventing the encapsulant from intrusion, wherein a rib-shaped protrudent member provided only around the liquid reservoirs of the trenched top board is supplemented to the ink head constitution as disclosed in the Japanese Laid-open Patent Application Number: 3-101957 (1991), has been disclosed in a Japanese Laid-open Patent Application Number: 5-138896 (1993).
However, it requires a considerably high pressurizing force to deform the rib-shaped protrudent member provided around the liquid reservoirs though the ink head constitution disclosed in a Japanese Laid-open Patent Application Number: 5-138896 (1993) can actually prevent the encapsulant intrusion to a certain extent. Aforesaid high pressurizing force does not have so ill effect indeed so long as an array density of the ink paths on the trenched top board is low. If the array density exceeds 600 dpi, the force deforms even ink path walls because a wall thickness should be thinned due to the high array density. On the contrary, when the pressurizing force of the pressurizing member is set up to be low in order not to deform the ink path walls, the adhesion of the ink path area is worsened than so far because aforesaid protrudent member is formed higher than the contacting area of the ink path to be contacted with the substrate.
When the arraying density of the ink paths is densified, above-mentioned deformation in the ink path walls induced by the pressurizing force of the pressurizing members takes place even in the constitution without aforesaid protruded member provided on the trenched top board. Actually, when a high pressurizing force generated by the pressurizing member 6 is applied to a portion 5 to be pressurized which is mounted on the trenched top board shown in FIG. 5 for illustrating a longitudinally sectioned partial view of a conventional ink-jet recording head, a common liquid reservoir side of the ink paths 4 is deformed around a portion B, which serves as a supporting point, so that an ejecting port side N of the ink paths 4 formed on the trenched top board 1 floats from the substrate 2 because a rigidity of the common liquid reservoir side of the ink paths 4 cannot be enforced compared with the ejecting port side N. To float the ejecting port side N of the ink paths 4 formed on the trenched top board 1 from the substrate 2 has severer effects on the printing quality.